Tunnel driving machine



May 27, 1969 E. LAUBER 3,446,535

TUNNEL DRIVING MACHINE Filed March 6, 1967 8 y 7 i if? 2s 4/ f/f w 9% zo36 I3 22 A INVEN'IOR. ms-|- una@ BYl 44W May 27 1969 E. LAUBER 3,446,535

TUNNEL DRIVING MACHINE Filed March 6, 1967 sheet Z ora Fla/3 INVENTOR.fm/ST LAM E l@ BY www May 27, 1959 E. LAUBER 3,446,535

TUNNEL DRIVING MACHINE Filed March 6. 1967 f4 PX'JVENTOR. 6m51- LauweACW United States Patent O Int. Cl. E21d 9/00; E01f 3/04 U.S. Cl. 299-3117 Claims ABSTRACT F THE DISCLOSURE A machine body is supported by arunning gear and provided with propulsion means for feeding the bodyforwardly. A main column extends transversely to the axis of the tunneland is firmly connected to the forward end portion of the machine body.The main column is adapted to be independently restrained in the tunnel.At least one segment member is pivoted to the main column on an axiswhich is transverse to the tunnel axis and has an arcuate peripheralface conforming to a part of the profile of the tunnel. A plurality ofinserted-tooth cutter heads adapted to cut at their periphery aremounted on said arcuate peripheral face.

This invention relates to a tunnel driving machine. The previously knownmachines comprise a tool carrier which consists of a rotary drum orrotary spider. The tools consist in many cases of roller bits, which areused on the rotary drum in different forms and arrangements. Inrelatively large machines, two concentric drums are used, which rotatein opposite senses to obtain a better balance of the considerable torquewhich is effective. A plurality of roller bits may be combined in aunit, with which a separate drive is associated. These roller bitsrotate faster than the slowly rotating drum and in a sense oppositethereto so that a torque compensation is also obtained. The penetrationof the roller bits into the rock requires an almost complete destructionof the rock structure, and very strong forces must be applied by the:tools in the direction of the axis of the tunnel. As a result, a verystrong and rigid structure is required for the drum, its mounting, thefeeding means and the means for restraining the machine on the walls ofthe tunnel. For this reason, tunnel driving machines provided withroller bits are too heavy and uneconomical for tunnels large indiameter, particularly in hard rock.

To improve this situation, protruding chisel-type bits have beenprovided on the rotary drum and have been used to cu-t concentricgrooves into the tunnel face, and the roller bits have been used asbreaking rolls, which break off the lands between the grooves. Where tworotary drums having opposite senses of rotation are employed, a drivingeven of tunnels large in diameter is possible with this arrangement butonly in very soft rock having no hard inclusions. The protrudingchisel-type bits break in harder rock o-r where inclusions occur.

It is also known to use only cutting teeth as tools and to arrange arelatively large number of such teeth in a staggered arrangement on aplurality of arms. This design is suitable only for driving tunnels invery soft material, such as loam, clay or t-he like, because rock evenif it has only a low hardness requires an excessively high torque fordriving the tool carriers. A further improvement has been achieved inthat the cutting teeth were used on Vinserted-tooth cutter heads, whichperform a rotation of their own in addition to the rotation of the drum.Such machines have a strongmain shaft and a hollow shaft, which isrotatably mounted on the main shaft. These two shafts are driven atdifferent speeds by a common motor. A hollow carrying body is secured tothe hollow shaft and a set of gears, driven by the main shaft, ismounted in said body and serves for imparting rotation to insertedtoothcutter heads or circular series of tools, which are rotatably mounted onthe carrying body, which rotates at low speed. All teeth are constantlyin engagement and their cutting paths intersect so that a high wear ofthe tools results. As the circular series of tools or insertedtoothcutter heads rotate in the same sense of rotation, the torques exertedon the carrying body add to each other and exert excessively highstresses on the carrying body, the main shaft and the mounting. Becausethe face of the tunnel is being machined, strong feeding forces in thedirection of the tunnel axis must be applied. Such machine cannot beeconomically built for use in hard rock and tunnels large in diameterbecause the machine would be too heavy and too clumsy.

A significant improvement can be obtained if the periphery of the tunnelrather than the tunnel face is machined. In this known process, aplurality of cermet-tipped tools are radially inserted in a cutter headdisc, as in inserted-tooth milling cutter heads. A plurality ofinsertedtooth cutter heads provided with a transmission and a motor aresecured in concentric circles on a rotary drum so that the cutting edgesof the tools perform a rotation about the axis of the inserted-toothcutter heads and an additional rotation about the tunnel axis in anepicycilc motion. The main machining work is performed at the peripheryof the inserted-tooth cutter heads. As the machine is being fed, theteeth advance along a helical path and the cutting edges act in adirection which is approximately tangential to this path. This processenables a machining even of hard rock because the resultant of thecutting forces at the teeth requires only a low torque for driving thedrum. If the feed increment is larger than the width of the cutting edgeo'f the tools, it will be sufficient to disintegrate only part of thematerial whereas the remainder can be broken off beside the cuttingedges. In this way the cermet consumption, which is economicallysignificant, can be highly reduced. The application of this process fordriving tunnels having a large inside diameter, however, involvesserious disadvantages because the transmission of the cutting forcesfrom the large drum through its mounting to the body of the machine isdifficult and the machine becomes very heavy. All known tunnel drivingmachines have the further disadvantage that they can form onlycircular-section tunnels because a drum or spider rotating about theaxis of the tunnel is used as a tool carrier and it is not possible toremove material unilaterally, e.g., for an enlargement of existingtunnels. Furthermore, the body of the machine is of considerable lengthso that the point where the tunnel supports are installed must lie aconsiderable distance behind the face.

It is an object of the invention to eliminate these disadvantages andprovide a tunnel driving machine which is relatively simple inconstruction and enables the formation of tunnels, ducts or the likehaving a large inside diameter and different sections and even in hardrock and which permits of a removal of material also on one side and aninstallation of supports closely behind the tunnel face.

The invention is based on a tunnel driving machine which comprises aplurality of rotary, inserted-tooth cutter heads cutting at theirperiphery and resides essentially in that the inserted-tooth cutterheads are mounted at the periphery of at least one segment member, whichconforms to a part of the tunnel profile, and which is pivotally mountedon an axis which is transverse to t-he tunnel axis to a main column,which extends transversely to the tunnel axis and which can beindependently restrained in the tunnel and is firmly connected to arearwardly extending machine body, which is provided with a running gearand feeding means, the propelling and steering movements being performedwhen the main column is released and the segment member has been swungback. There is no longer a rotary drum or the like but the tool carrierconsists of the segment member, which can be selected to conform to anydesired tunnel profile and is provided with the rotary, inserted-toothcutter heads, which are spaced as closely as possible, and the segmentperforms a pivotal movement about the main column in operation. If thereis only one segment member, the range of the pivotal movement will beabout 180. With two segment members this range may be divided into twoparts of about 90 each. The cutting forces are transmitted from` thesegment member to the main column and from the latter directly to thetunnel so that the body of the machine need no longer be used for atransmission of force. As the feeding and steering movements areperformed at a time when the inserted-tooth cutter heads are not incontact with the rock, the large forces which occur during cutting actonly on the inserted-tooth cutter heads, the segment member and the maincolumn and have no influence on the feeding and steering means. Thesupports for the tunnel may be installed around the body of the machinebehind the main column. As the cutting forces are transmitted from themain column directly to the tunnel, the solution can take up alsounilateral pressure so that the machine according to the invention issuitable for a unilateral enlargement of existing tunnels or for anenlargement of length portions of the tunnel being driven. Owing to itsspecial design, the machine requires a lateral guidance only in a shortlength so that a tunnel can be driven with a very small curve radius,e.g., for forming cavern branches. As inserted-tooth cutter heads areused which cut on their periphery and are provided with cermet-tippedteeth, of course, the use of the machine is not restricted by thehardness of the rock. The main column is usually restrained to extendvertically at the center of the tunnel. At the beginning of the cuttingoperation, the segment member is in a lateral position and transverse tothe feeding direction and is then swung forwardly so that the face ofthe tunnel is formed according to the same profile as the side walls. Asthe excavation takes place along a curved surface, the tunnel face has avery high stability. This is an advantage mainly in a tunnel driven inrock which is soft or of low inherent stability. When the segment memberhas entirely traversed its range of pivotal movement, the main column isreleased and the body of the machine is fed and takes the main columnalong. The latter is then again restrained in the tunnel and themachining of the tunnel face is repeated by a pivotal movement of thesegment member. The feed increment in the direction of the axis of thetunnel may be so large that only part of the rock is cut and theremainder is broken olf. Alternatively, the main column may behorizontally disposed so that arches can be formed, e.g., as a roof oflarge caverns for power plants. The segment member can be replaced byanother segment member, which may be differently shaped, whereas theother parts of the machine remain the same. ln this way, the machine canbe used in an economical manner for driving tunnels having differentproles and inside diameters. The tunnel driving speed of the machine maybe increased if the segment member is replaced by two segment membersmoving in opposite directions. Owing to the provision of a main column,the machine according to the invention simplifies the power supply tothe several tool units as only cables or flexible pressure oil tubesextend from the body of the machine through the column into the segmentmember and the cooling water conduit for dissipating heat from motorsand transmissions for the inserted-tooth cutter heads can be insulatedin a similar manner. Where a rotary drum or similar means are employed,all lines must be connected by slip rings.

`If the main column has a vertical orientation, the pivotal movement ofthe segment member during operation results necessarily in the formationof a at tunnel floor. This is desirable in most cases, The roof of thetunnel remains flat too. As the roofs of the tunnel should have the formof `an are of a circle or ellipse, depending on the tunnel profile, inorder to increase the stability, the invention teaches to provideadjacent to the roof behind the main column at least one inserted-toothcutter head, which is pivotally movable about the tunnel axis or an axiswhich is parallel thereto. This insertedtooth cutter head may be carriedby a pivoted arm, which carries a driven pinion, which is in mesh with atoothed arcuate guide member so that the desired pivotal movement isobtained. The arcuate guide member may extend along a non-circular curveand the pivoted arm may be adjustable in length so that the roof isformed according to an elliptical or similar prole.

To facilitate the restraining and release of the main column in thetunnel, the main column consists of at least two parts, which aretelescoped and extensible by hydraulic pressure, and t-he main columncarries at its ends two engaging plates, for instance, `a oor plate anda roof plate.

For the pivotal movement of the segment member, the same is engaged by areciprocable endlless chain or the like, which extends in an arcuateguide member, which is coaxial with the main column. Where two segmentmembers `are used, it will be understood that two chains, which aremovable independently of each other, must be provided in the arcauteguide member.

In a further embodiment of the invention, the body of the machine isprovided at the rear with a running gear bearing on the tunnel oor andin its forward portion with feeding means consisting of two lateralpivoted legs, which can be set to the tunnel floor and are adjustable inlength and have shoes, which are articulatedly connected to the machinebody by an obliquely rearwardly extending linkage, which is alsoadjustable in length. When the pivoted legs have been adjusted in lengthto engage the tunnel floor, the main column may be released from thetunnel and the machine body will then carry the main column and thesegment member. When the main column has been retracted from the tunnelroof and the segment member has been pivotally retracted, the center ofgravity of the machine must lie behind the pivoted legs so that .afurther increase of the length of said legs will lift the main columnfrom the tunnel floor and cause it to tilt rearwardly to some extent.The feed movement proper can now begin. This movement is usuallyeffected by a reduction of the length of the linkage which connects theleg shoes to the machine body so that the pivoted legs are inclinedforwardly and push the machine .ahead until the column bears again onthe tunnel floor and is restrained. Thereafter the pivoted legs can beretracted. The pivoted legs are connected to the machine body and theshoes by universal joints so that a movement in all directions ispossible. As the pivoted legs are laterally arranged, they may be usedalso to correct a lateral inclination of the main column and of the bodyof the machine.

The running gear which supports the rear portion of the machine body isprovided with a carrying frame, which is pivoted on `a horizontal axisextending transversely to the direction of travel and which is providedwith a bearing, which is adjustable in height and receives a trunnionprovided at the rear end of the body of the machine. By an adjustment ofthis bearing, the body of the machine is raised or lowered at its rearend so that the released main column is forwardly or rearwardlyinclined. When the main column is subsequently restrained again, thetunnel will be driven on an upgrade or downgrade.

The body of the machine is also provided with later- A ally extendingarms, which have skids connected to them, which are adjustable in ahorizontal plane. These skids are guided by the side walls of the tunneland can be adjusted to enable `a lateral steering of the machine beingfed. The arms enable a lateral steering of the machine being fed. Thearms may be pivotally retractable so that they will not obstruct areverse movement of the machine. For a reverse movement, the machinebody is provided with an additional running gear, which is selectivelyengageable with the tunnel oor and adapted to be driven.

'I'he body of the machine consists suitably of a plurality of boxsections, which are ange-connected and accommodate the drivers stationwith the switchgear and controls, hydraulic units and the like, so thatthe driver is well protected from dust, moisture, heat, noise and thelike. The sensitive equipment is also well accommodated. As the body iscomposed of a plurality of sections, it can easily be taken apart andassembled and the sections can be individually transported as separateunits.

The invention will be explained more fully with reference to theaccompanying drawing, in which the subject matter of the invention ispartly diagrammatically shown by -way of example.

FIG. 1 is a side elevation showing a tunnel driving machine with thechain guide and t-he conveyor means shown in section.

FIG. 2 is a top plan view showing the machine, the roof cutter and itsguide being omitted.

FIG. 3 is a transverse sectional View taken through the machine on lineIII-III of FIG. 2 but with laterally swung segment members intended fora different, horseshoe-shaped tunnel profile.

FIG. 4 is also a transverse sectional view which is taken through themachine in the left-hand half of the drawing as in FIG. 3 and in theright-hand half of the drawing on line IV-IV of FIG. 2, the segmentmembers being selected for a `circular tunnel profile.

FIGS. 5 to 9 show diagrammatically the cutting operation performed by amachine having two segment members.

FIGS. -12 show the cutting operation performed by a machine having onlyone segment member.

FIGS. 13 to 17 illustrate diagrammatically the feed movement of themachine.

FIGS. 18-20 show the steering means of the machine and FIG. 21 shows themachine during a reverse movement. 1

The machine comprises a main column, which extends vertically in thecenter of the tunnel. This column consists of two parts 1, 2, which canbe telescopically extended under telescopic pressure, and carries at itsends a oor plate 3 and a roof plate 4. The main column 1, 2 is rmlyrestrained between the floor and roof of the tunnel in operation. Arearwardly extending machine body 6 is rigidly connected the main columnand is composed of a plurality of box sections. An arcuate guide member7, which is coaxial with the main column 1, 2, is provided above themachine body 6. Two endless chains 8 consisting of three strands eachextend in said guide member. The two chains 8 extend around sprockets 9,10 (FIG. 2), which are driven. The sprocket 10 is additionallyadjustable for tensioning the chains. Each of the two chains hasseparate sprockets so that it can be driven independently of the other.The direction of the drive is reversible. Each of the two chains 8 isconnected to one of segments 11, 12, each of which is pivoted to themain column 1, 2 and conforms to a part of the tunnel profile.Inserted-tooth cutter heads 13, which cut at their periphery, areprovided in a closely spaced arrangement at the periphery of the segmentmembers 11, 12. Each of said cutter heads is combined with atransmission and a motor in a tool unit. The segment members 11, '12 arepivotally reciprocated about the main column 1, 2 by means of the chains8.

The form of the segment members 11, 12 depends on the profile of therespective tunnel, as is apparent from FIGS. 3 and 4. The number ofinserted-tooth cutter heads 13 and of the tool units depends on thenumber of segments and the size of the tunnel prole. The drivingoperation is performed in such a manner that the floor and roof of thetunnel remain at. To form the roof of the tunnel with the curvaturewhich is required for reasons of stability, a further inserted-toothcutter head 14 with a suitable drive unit is provided adjacent to theroof behind the main column 1, 2. This drive unit is secured to apivoted arm 15, which is coaxial with the tunnel and carries a drivenpinion 16 in mesh with a toothed arcuate guide member 17 (FIGS. 1 and4). Different arcuate guide members may be used for adaptation to thetunnel profile. The pivot of the arm 15 is also adjustable in height.

The main column 1, 2 is iirmly restrained in the tunnel during thecutting operation and must be released for the feed movement. Themachine body 6 is provided with two lateral pivoted legs 18, whichconsist of a cylinder and piston for adjustment in length and areconnected by universal joints to the machine body or side brackets '19of the machine body and to their shoes 20. The shoes of the pivoted legsare articulatedly connected to the machine body 6 by a linkage 21, whichextends obliquely and rearwardly and which is also adjustable in length.At its rear end, the machine rests on two supporting crawlers 22, whichare not driven and form the running gear. The crawlers 22 support acarrying frame 24, which is pivoted about the axis 23 and is providedwith a bearing. This bearing is adjustable in height by a powerdrivenscrew and receives a trunnion 25, which is provided at the rear end ofthe body 6 of the machine. The screw can be rotated to swing the bearingwith the trunnion 25 and the body 6 of the machine upwardly anddownwardly for a correction in height. For this purpose, the main columnmust be released so that it can assume the desired inclination. Thiswill result in an inclination of the plane in which the segment members11, 12 are pivotally movable and in a rise or fall of the tunnel roof(FIG. 19).

For a reverse movement of the machine (FIG. 21) an additional drivingcrawler 26 is provided, which has a drive of its own and which is raisedduring the operation of the machine and is hydraulically engaged withthe tunnel floor only for a reverse travel.

Two laterally extending arms 27, which carry skids 28, serve forlaterally guiding and steering the machine in the tunnel. The skids 28can Ibe adjusted in a horizontal plane with the aid of hydraulic jacks29. Long cylinderpiston units 30 are incorporated at the rear -in thearms 27 so that the rear spars of the arms can be shortened to swing thearms 27 rearwardly to a position in which they do not obstruct thereverse movement of the machine. It will be understood that the armsmust be articulated in such a manner that this pivotal movement and anadjustment of the skids 28 is enabled. The rearward pivotal movement ofthe arms willswing back also the segment members 11, 12 beyond theirtransverse initial position so that the inserted-tooth'cutter heads 13will not contact the side walls of the tunnel d-uring a reversemovement.

With tunnels large in cross-section, tunnel supports -must be installedsoon as any settlement of the rock and large forces released therebymust be avoided. Where the machine according to the invention isemployed, the walls of the excavation can be supported immediatelybehind the roof cutter 14 and the skids 28. FIGS. l and 2 show by way ofexample the use of vsteel rings 31 as supports.

For the removal of the excavated material, inclined guide plates 32, 33are provided one under the other on the sides of the segment members,and a vibrating chute 34 is provided under the guide plates and feedsthe excavated material to a rotary feeder 35?, which is mounted on themain column and transfers the material to a rearwardly moving beltconveyor 36. The debris which are removed from the oor of tunnel arereceived by a scraper ight conveyor 37 and transferred over a trough 38(FIG. 1) to another belt conveyor 39 (FIG.

2). With tunnels small in cross-section, there is no need for a removalof material in the upper part of the tunnel so that the scraper flightconveyor 37, the trough 38 and the belt -conveyor 39 are sufficient inthis case.

The machine operates as follows: In accordance with FIG. 5, the machinehas excavated material along the semicircle indicated by a thick lineduring the last cycle of operation. The main column 1, 2 has then beenadvanced by the feed increment V and the segment members 11, 12 carryingthe inserted-tooth cutter heads 13 are in the initial positions a, b.Both segment members are now swung forwardly toward the center of thetunnel by means of the chains 8, and the inserted-tooth cutter headsexcavate in the area which -is hatched in FIG. 4. The width of cutincreases as the pivotal `movement proceeds. To obtain a uniform load onthe tools throughout the cutting path, the segment members 11, 12 may bemoved initially faster and be gradually slowed down until they havereached the positions c, d (FIG. 6). For removing the rock also in thearea c-d between the inserted-tooth cutter heads 13, the pivotalmovement of the segment member 11 is continued when the return movementof the segment member 12 has already begun (FIG. 7). For a symmetricaltunel-driving operation, the segment member 12 is swung further toposition d in the next cycle of operation while the segment member 11 isreturning (FIG. 8). While the tunnel face is being machined, the roofcutter 14 is operated with its pivoted arm 15 moving along the arcuateguide member 17 so that the arcuate portion remaining on the roof of thetunnel is cut in the width of the feed increment V. FIG. 9 shows bothsegment members 11, 12 again in the initial position at a and b, wherethey remain during the following feed movement, in which the segmentmembers 11, 12 follow the entire machine.

In FIGS. 10-12 there is only one segment member 11, which must -be swungthrough about 180 to move from the initial position a to the endposition b, which corresponds to the initial position reached when thefeed movement of the machine was completed. With a single segment memberjust as with a machine having two segment members, the feed increment Vexceeds the width of the teeth so that the rock is undercut and thelands of rock are broken off. The feed increment -is equal to the sum ofthe tooth width and the breaking width.

The means for feeding and steering the machine do not change theirposition during the cutting operation and remain in the so-calledoperative position, in which the main column 1, 2 is firmly restrainedand takes up the cutting forces. The machine body 6 rests at its rearend on the supporting crawlers 22 and the pivoted legs 18 are retracted(FIG. 13). When the cutting operation has been terminated, the pivotedlegs 18 are extended so that their shoes 20 engage the tunnel floor. Thepiston drives 29 are operated to retract the skids 28 to some extentfrom the side walls of the tunnel. As the center of gravity S of themachine is disposed behind the pivoted legs 1-8, the machine body swingsabout the axis 23 of the carrying frame 24 and the floor plate 3 of themain column is lifted off the oor (FIG. 14) when the main column 1, 2has been retracted and the lifting force of the pivoted legs increases.The linkage 21 is now shortened so that the pivoted legs 18 areforwardly inclined. As the shoes 20 are loaded by the weight of themachine and have a higher ground friction, they dene a fulcrum whereasthe two supporting crawlers 22 roll forwardly by the feed increment Vwhile the pivoted legs perform a pivotal movement (FIG. 15). The maincolumn has then assumed its new position. The two parts 1, 2 are pushedapart to restrain the main column in the tunnel 'and a new cuttingoperation can begin (FIG. 16). The linkage 21 can be extended and thepivoted legs 18 be shortened at the same time to bring the feeding meansinto position for a new `feeding operation (FIG. 17).

Before the main column is restrained in the tunnel when the feedincrement has been performed, the position of the machine in the t-unnelcan be exactly measured so that any directional corrections can beeffeced before the new cycle of operation begins. To correct lateraldeviations 0f the axis of the machine body from the desired tunnel axisor for driving right-hand or left-hand curves, the skids 28 are adjustedwith the aid of the cylinder-piston units 26 (FIG. 18). Deviations ofthe machine from the tunnel axis in a vertical plane can be compensatedby an adjustment of the bearing for the trunnion 25 in the carryingframe 24, as is shown in FIG. 19. A lateral inclination of the maincolumn 1, 2 can be corrected by an increase or decrease of the length ofthe pivoted legs 18, as is shown in FIG. 20.

A reverse movement is required for maneuvering and for moving themachine out of the tunnel. Whereas the feed movement is to be effectedin small steps, the reverse movement should be faster and continuous.Before a reverse movement, all parts which contact the tunnel walls mustbe retracted. For a reverse movement, the crawler 26 is engaged with thetunnel floor when the pivoted legs 18 have been retracted. The maincolumn 1, 2 can then be released and is subsequently lifted off thetunnel floor by a further extension movement of the crawler. The machinerests now only on the crawlers 22 and 26 and can be propelled by thedrive means for the crawler 26.

What I claim is:

1. A tunnel driving machine, which comprises a machine body, a runninggear supporting said Imachine body, feeding means for feeding saidmachine body forwardly, a vertical main column arranged to extendtransversely to the axis of the tunnel being driven and firmly connectedto the forward end portion of said machine body and adapted to beindependently restrained in the tunnel being driven, at least onesegment member which is pivoted to said main column about an axis whichis arranged to extend transversely to the axis of the tunnel beingdriven and which has an arcuate peripheral face conforming to a part ofthe desired tunnel prole, a plurality of inserted-tooth cutter headsoperable to cut at their periphery and rotatably mounted on said arcuateperipheral face, and additional inserted-tooth cutter head meansdisposed behind the main column adjacent to the roof of the tunnel beingdriven and pivotally movable about an axis which has the same directionas the axis of the tunnel being driven.

2. A tunnel driving machine as set forth in claim 1, in which said maincolumn is adapted to be released and said segment member is adapted tobe pivotally retracted to enable feeding and steering movements of saidmachine.

3. A tunnel driving machine as set forth in claim 1, which comprises ana-rcuate rack carried by said machine body, a pivoted arm carrying saidadditional insertedtooth cutter head means, and a pinion carried by saidarm and in mesh with said arcuate rack.

4. A tunnel driving machine as set forth in claim 1, characterized inthat said main column comprises two telescoped parts, which are adaptedto be moved apart by hydraulic force.

5. A tunnel driving machine as set forth in claim 1, in which said maincolumn has two engaging plates at opposite ends.

6. A tunnel driving machine as set forth in claim 1, which comprises anarcuate guide member carried by said machine body and coaxially disposedwith respect to said main column, and a flexible tension element inguided engagement with said guide member and connected to said segmentmember, and drive means for reciprocating said tension element.

7. A tunnel driving machine as set forth in claim 1, which compriseslaterally extending arms secured to said machine body, and skids whichare carried by said arms and movable in a horizontal plane.

8. A tunnel `driving machine as set forth in claim 7, in which said armsare pivotally retractable.

9. A tunnel driving machine as set forth in claim 1, in which saidmachine body comprises a plurality of box sections flange-connected inend to end alignment, and a drivers station, switching and control gear,and hydraulic units accommodated in said box sections.

10. A tunnel driving machine as set forth in claim 1, rwhich comprises ascraper flight conveyor arranged to rest on the tunnel lloor andsurrounding said main column, an inclined trough succeeding said scraperflight conveyor, and a rearwardly extending belt conveyor succeedingsaid trough.

11. A tunnel driving machine, which comprises fa machine Ibody, arunning gear disposed at the rear end of the machine, arranged to reston the iloor of the tunnel being driven and supporting said machinebody, feeding means for feeding said machine body forwardly, the feedingmeans comprising two pivoted legs connected to the sides of the forwardportion of said machine body and adjustable in length and selectivelyengageable with the tunnel floor, shoes carried by said pivoted legs atthe outer ends thereof, and linkages adjustable in length, articulatedlyconnected to said shoes and exteding rearwardly obliquely from saidshoes to said machine body, to which they are articulatedly connected, amain column arranged to extend transversely to the axis of the tunnelbeing driven and rmly connected to the forward end portion of saidmachine body and adapted to ybe independently restrained in the tunnelbeing driven, at least one segment member which is pivoted to said maincolumn about an axis which is arranged to extend transversely to theaxis of the tunnel being driven and which has an arcuate peripheral faceconforming to a part of the desired tunnel profile, and a plurality ofinserted-tooth cutter heads operable to cut fat their periphery androtatably mounted on said arcuate peripheral face.

12. A tunnel driving machine as set fo-rth in claim 11, which comprisesuniversal joints connecting said pivoted legs to said machine body andto said shoes.

13. A tunnel driving machine as set forth in claim 11, in which saidmain column is arranged to be retractable from the roof of the tunnelbeing driven and said segment member is pivotally retractable to aposition in which the center of gravity of the machine is disposedbehind said pivoted legs.

14. A tunnel driving machine as set forth in claim 11, which comprises acarrying frame pivoted to said running gear about a horizontal axiswhich is transverse to the direction of travel of said running gear, abearing which is carried by said carrying frame and adjustable inheight, and a trunnion which is connected to the rear end portion ofsaid machine body and carried by said bearing.

15. A tunnel driving-machine as set forth in claim 11, which comprisesan additional running gear, which is connected to said machine body andarranged to be selectively engageable with and disengageable f-rom theoor of the tunnel being driven, and drive means operable to drive saidadditional running gear in the longitudinal direction of said machine.

16. A tunnel driving machine, which comprises a machine body, a runninggear supporting said machine body, feeding means for feeding saidmachine body forwardly, a main column arranged to extend transversely tothe axis of the tunnel being driven and firmly connected to the forwardend portion of said machine body and adapted to be independentlyrestrained in the .tunnel being driven, at least one segment memberwhich is pivoted to said main column about an axis which is arranged toextend transversely to the axis of the tunnel being driven and which hasan arcuate peripheral face conforming to a part of the desired tunnelprofile, oblique guide plates carried by said segment member on thesides thereof and disposed one under the other, a plurality ofinserted-tooth cutter heads operable to cut at their periphery androtatably mounted on said arcuate peripheral face, a rotary feedermounted on said main column and arranged to receive detached materialfrom said inserted-tooth cutter heads Via said guide plates, arearwardly extending belt conveyor arranged to receive said materialfrom said feeder, a scraper flight conveyor arranged to rest on thetunnel oor and surrounding said main column, an inclined troughsucceeding said scraper ight conveyor, and a rearwardly extending beltconveyor succeeding said trough.

17. A tunnel driving machine as set forth in claim 16, which comprises avibratory chute carried by said segment member and operable to receivedetached material from said guide plates and to deliver it to saidrotary feeder.

References Cited UNITED STATES PATENTS 14,483 3/ 1856 Wilson 299-86 X2,211,751 8/ 1940 McCarthy 299-31 X 2,752,143 6/1956 Joy 299-312,760,766 8/ 1956 Mayo 299-86 X 3,290,095 12/ 1966 Bredthauer 299-71 X3,295,892 1/1967 Winberg et al. 299-31 3,355,215 1l/l967 Haspert et al299-31 X ERNEST R. PURSER, Primary Examiner.

U.S. Cl.. X.R.

